1. Field of the Invention
The present invention relates to a direct exposure system that performs a direct exposure process, using drawing data, for forming a desired exposure pattern on a substrate and a user interface that allows the direct exposure system to perform the direct exposure process using the drawing data for forming the desired exposure pattern on the substrate in the manufacture of circuit boards or semiconductor devices.
2. Description of the Related Art
In manufacturing processes of circuit boards, a desired pattern is formed by forming a resist film that is a photosensitive resin film on a substrate, exposing the resist in the desired pattern and, then, performing an etching process on the substrate.
In an exposure process using photomasks, as a substrate on a stage and a photomask are aligned with each other mechanically by moving them relatively, accuracy is degraded.
Typically, in an exposure process, as the effects of physical and chemical parameters are profound, the substrate in exact accordance with drawing data cannot always be obtained after the exposure. For example, as the substrate itself may expand, shrink or distort due to ambient temperature of the substrate, mechanical stress applied to the substrate and the like, it is necessary to empirically optimize different process conditions (i.e., to empirically make adjustments of different process conditions) so that the desired pattern can be obtained by remaking photomasks of different layouts several times in consideration of such expansion, shrinkage or distortion.
Further, before mass production, in order to obtain optimal values for various conditions such as the dose of exposure, the exposure speed, the focus of light sources and so on (hereinafter referred to as “exposure conditions”), a set of inspections called “optimization” must be performed repeatedly to determine the optimal exposure conditions.
However, in the exposure process using the photomasks, as the photomasks are needed even at the experimental stage, where inspections are repeated many times, not to mention in the mass production of substrates, it is costly and very uneconomical to manufacture the masks.
For the reason described above, in recent years, a direct exposure (or maskless exposure) method without using photomasks has been proposed.
According to the direct exposure method, the drawing data can be corrected easily according to the distorted substrate and, therefore, improvements can be made such as increase in manufacturing accuracy, increase in yield, shortening of delivery times, reduction of manufacturing cost and so on.
Examples of the direct exposure method include a technique set forth in Japanese Unexamined Patent Publication No. 10-112579. According to this technique, when a resist formed on a substrate is exposed, pattern data is generated according to a pattern to be exposed, then, this pattern data is input to Digital Micromirror Device (DMD), a plurality of micro mirrors of DMD are tilted according to the pattern data and, then, light is projected on DMD so that the resist is illuminated by the light reflected from the micro mirrors and exposed in a shape according to the pattern data.
In either the exposure method using the photomasks or the direct exposure method without using the photomasks, the exposure process is performed with regard to given drawing data under certain constant conditions. In other words, the exposure conditions applied to exposing one substrate are always constant.
Therefore, in the process for determining the exposure conditions (conditioning) before the start of mass production of the exposed substrates, in order to test various exposure conditions and determine optimal exposure conditions, a large number of substrates must be exposed even in the direct exposure method, not to mention in the exposure method using the photomasks.
In comparison with the exposure method using the photomasks, the direct exposure method is inexpensive in terms of cost because it does not use the photomasks, but both methods are similar in that a plurality of substrates must be exposed in the process for determining the exposure conditions and, therefore, they are not cost-effective. Further, as the exposure conditions must be set again every time the exposure of one substrate to which certain exposure conditions are applied is completed, these methods take effort and time. Still further, not only in the process for determining the exposure conditions, but also in other processes, it is convenient if the necessary exposure conditions can be set for the exposure devices easily in a short time.
In view of the above problems, it is an object of the present invention to provide a direct exposure system and a user interface that can facilitate determination and setting of exposure conditions.